Float interlock system for washing machines



July 13, 1954 0Q L. CLARK -FLOAT- INTERLOCK SYSTEM FOR WASHING. MACHINES Filed March 2, 1951 2 Sheets-Sheet l Inventor? David L. C l ark,

His Attorn eg.

1 Filed March 2, 1951 y 1954 I I P. L. CLARK 2,683,363

FLOAT INTERLOCK SYSTEM FOR WASHING MACHINES 2 Sheets-Sheet 2- David Clark,

1 I by His Attorn e5.

Patented July 13 1954 FLOAT INTERLOCK SYSTEM FOR WASHING MACHINES David L. Clark, Allentown, N. J assignor to Gencral. Electric Company, a corporation of New York Application March 2, 1951, Serial No. 213,546

8 Claims.

This invention relates to an improved washing machine of the single basket, wash and spin-dry yp and in particular, to an improved control for such machines.

A presently well-known type of domestic Washing machine utilizes a timer operated control system under the dictates of which the machine fills to overflowing a clothes receptacle or basket within which the clothes are .placed and then upon the accumulation of a relatively small amount of overflow water in a tub'within which the basket is mounted for rotation on a vertical shaft the rising float of a float operated switch shuts off the water and energizes a circuit for the operation of a motor which drives mechanical agitating means within the basket. The basket during this cycle is held stationary by suitable brake means. After a predetermined washing period the control energizes a valve to direct fluid under pressure to a combined clutching and brakingsystem which releases the brake and disconnects the agitator and couples the basket shaft through a torque limitin clutch directly to the motor which rotates the basket at a high speed to remove the washing liquid by centrifugal action. The liquidcollects in the tub and is pumped therefrom by a drain pump which is operated at the appropriate time by the program controller. The basket is refilled with clear rinsing water, again to overflowing, and the float control switch institutes operation of the mechanical agitator so that the clothes are thoroughly agitated in the rinse water. The rinse water is then extracted by spinning the clothes basket which operation is instituted by the action of the solenoid controlled valve in the hydraulic pressure system and the rinse water is removed by the pump. It will be understood that there may be one or more rinsing periods. Generally speaking, a washing machine utilizing the essentials of the foregoing control system is described and claimed in the presently pending application of Thomas T. Woodson, Serial No. 639,816, filed January 8, 1946 for Control for Automatic Washing Machine, now Patent No. 2,561,257, patented July 17, 1951, and owned by the General Electric Company, assignee of the instant application. A program control switch useful with such a machine is disclosed and claimed in the presently pending application of Harold A. Jones, Serial No. 33,943; filed June 19, 1948, for Automatic Washing Machine Control, now Patent No. 2,608,082, and likewise owned by the General Electric Company.

The. machineof the Woodson type above noted 55 taken on lines 3--3 of Fig. 2, the tub being empty requires a separately motorized drain pump in view of the fact that its operation is correlated to the several cycles. I have devised a control system pursuant to which the drain pump may be directly mounted on an extension of the drive motor shaft, thus eliminating the necessity for a separately powered pump and simplifying the assembly and maintenance of the machine.

It is an object of my invention to provide means whereby the separately powered drain pump may be dispensed with by mounting the pump directly on the motor shaft so as to operate it continuously throughout the entire cycle of operations of the machine, except during the periods in which the machine is filling with water.

It is a further object of my invention to provide means whereby upon operation of the water level switch in response to the accumulation of a proper amount of overflow Water in the tub, a hold-in circuit is completed to maintain the control circuit in proper operating status even though immediately upon operation of the main drive motor the water which had accumulated in the tub is pumped out.

It is a further object of the invention to provide a control system which will adapt a continuously operating drain pump to otherwise standard and conventional sequence control systems.

In a presently preferred embodiment of my invention I provide an electromagnetic holding device which is energized upon the attainment of the desired level of overflow water to maintain the Water level switch in its closed position and thus establish and retain the standard control circuits even though the accumulated water will have quickly been removed by the operation of the pump. As will later appear, my hold-in circuit is made effective only during the cycles in which the further operation of the machine depends upon water accumulation Within the tub.

Other features and advantages will be apparent from the following detailed description of the invention'read in association with the accompanying drawings showing the application of my control system to an automatic domestic Washing machine and in which Fig. 1 is a side elevation of an automatic washing machine embodying the invention, certain portions of machine elements having been broken away to reveal underlying structure; Fig. 2 is a partial plan view of the bottom'of the washing machine tub showing a typical arrangement of float control switch embody- ,ing the invention; Fig. 3 is a sectional elevation and the float in its lower position; Fig. 4 is a view similar to Fig. 3 but showing the float held in raised position after the drain pump has operated to remove water from the tub; Fig. 5 is a schematic wiring diagram of the control system; and Fig. 6 is a representation of the program control cam operations.

In the accompanying drawings a domestic washing machine includes an imperforate container i provided with a bottom wall 2 which forms the bottom of a tub 3 within which water accumulates as presently described. Suitably resiliently supported within a central opening in said bottom wall is a casing l which contains a motor gearing and transmission (not shown) by means of which a basket 5 may be rapidly spun during water removal periods or a mechanical agitator e may be oscillated with the basket held stationary during washing periods. It will be noted that the side walls of the basket slope up wardly and outwardly to a zone of maximum diameter at which are a plurality of overflow ports i which define the normal level of washing liquid. Water is introduced directly into the basket by means of cold and hot water valves 8 and 9, the outlets of which merge into a single discharge spout Ill. The valves 5 and 9 are controlled by suitable solenoids H and 12. For simplification of the description of operation it will be assumed that solenoid controlled valve 8 is connected di" rectly to the cold water service line of the building and that solenoid controlled valve 9 is connected to the hot water line. By means which are fully described in the aforementioned Jones application warm water, represented by a mixture of hot and cool water, is supplied to the machine for all rinsing operations and may optionally be supplied for washing clothes which might be damaged in hot water. In the following description it will be assumed, however, that all of the washing operations are conducted in hot water, pursuant to which only the solenoid valve 9 would be energized and the rinsing operations are conducted with the mixture of hot and cold water following the joint operation of solenoid valves 3 and 9.

To further simplify the description it will be assumed that one wash and one rinse are employed, although it is understood that the washing may be preceded by a soaking period and followed by several rinsing periods. During washing and rinsing, Water is discharged from the spout ill into the basket 5 where it collects until the water level reaches the height of overflow ports 1', through which ports all excess water supplied will drain. This overflow water collects in the bottom of the tub 3 until a sufiicient quantity has been accumulated to raise a pivoted float it provided just above the bottom wall 2 of the tub. The float I3 is carried by an arm i4 passing through and pivoted in an extended neck portion !5 of a resilient sealing member [6 made of rubber or other suitable resilient material. The member 55 forms a seal to prevent the entry of water into a pocket ll formed in the wall 2 against which it is held in watertight relation by a plurality of bolts l8. These bolts pass through the wall 2, a turned under circular flange 59 formed on the member [6 and a sealing ring 20 so that when the bolts are tightened the flange to is compressed against the wall 2 by the sealing ring Ell. The bolts 18 in addition support beneath the wall 2 a cup 2! with a circular flange 22 fitting tightly against the underside of the wall. Within the pocket I! defined by the sealing member [6 and the cup 2| I provide a two-position electric switch 23 and an electromagnet 24. The switch 2-23 is provided with an upwardly biased plunger attached to a switch arm 26 (Fig. 5) which plunger when pushed downwardly moves the switch arm 26 from its normal engagement with its upper contact 21 into engagement with its lower con tact 28. Associated with and controlling the switch 23 is an arm 29 made of magnetic material and carried on the float arm it which is depressed when the float I3 is raised by the accumulation of water in the tub 3 so that it engages and pushes down the plunger 25 and at the same time engages the armature 39 of the electromagnet. If the holding coil 24 is energized at this time the arm 29 will be held in contact with the armature 3t by magnetic attraction and the float it will be kept in its raised position, as shown in Fig. i, even though the water in the bottom of the tub has been drained. While I have illustrated and described a float operated switch herein, obviously other types of water level sensing devices may be employed for operating switch 23 and pivo ing arm 29.

A pump (not shown) driven by the motor within the casing l will exhaust the water accumulated in the tub 3 whenever the motor is running. Consequently, as soon as the motor is started the water in the tub 3 will be drained and the float will no longer be supported in its raised position. Then except for the electromagnetic holding coil 24 the switch contact arm 26 would return to its normal position of engagement with its upper contact. As will be understood by the following description of the control circuit this would prevent proper operation of the machine during the washing and rinsing cycles.

Referring now to Figs. 5 and 6 in which all the control switches are shown in their open position and the switch 23 is shown with its contact arm in its normal position in engagement with its upper contact 2?, it can be readily seen that electromagnet 24 is necessary to the proper control of the operation of the machine. At the beginning of the wash cycle, as shown in Fig. 6, the switch IV is closed in response to the progr 'ai controller (not shown) which may be of any suitable type, such as that disclosed in the aforementioned Jones application. This completes a circuit to the solenoid 2 for the hot water valve 9, opening the valve and permitting not water to be discharged from the spout iii into the basket 5. This circuit remains energized until the overflow water from the basket 5 has accumulated the drain tub in suiiicient quantity to raise the float i3 which in turn causes the plunger to more the switch contact arm 25 away from its up er contact 21 and into engagement with lo contact 28. The circuit to the solenoid 5i thereby interrupted and at the same time a circuit through the electromagnet a relay 3|, and the main motor windin is completed. The start relay 3! is provided with a plunger 33 which carries a contact arm 3&- disposed below and arranged to bridge a pair of o en co ct members 35. The relay Si is of a sufficient rating that the plunger 3.3 will be raised to cause the contacts 35 to be bridged only when the high starting current for the motor is flowing through the relay coil. Bridging of the contacts com-- pletes a circuit through a starting capacitor and a start winding 3'? for the motor. When the motor comes up to operating speed its current requirements decrease and the start relay Si no longer provides sufiicient power to keep its plunger 33 in its raised position, permitting it to fall and open the contacts 35. Thus, the starting capacitor and start winding are automatically removed from the circuit. At this point in the cycle the motor is driving the clothes agitator because the switch I must be closed before the drive mechanism shifts to its spin position. Although the motor is also driving the drain pump and the water accumulated in the tub is being rapidly exhausted, the float i3 is held in its raised position by the electromagnet. Consequently, this circuit is undisturbed during the remainder of the wash period, even though the float supporting water is completely exhausted.

At the end of the wash period switches I and II are closed by the action of the program controller, the switch I completing a circuit through a spin valve solenoid 38 and the switch II completing a newcircuit through the starting relay 3| and the main motor winding 32 which has the eiiect of shunting the previous circuit through the electromagnet 24. Ehergization of the spin solenoid 38 causes the hydraulic'drive mechanism to shift from its normal agitate position to its spin position in the manner described in the aforementioned Woodson application so that the basket 5 will be rotated at high speed for centrifugal extraction of the wash water from the basket and clothes, as this wash water is thrown by centrifugal force to the point of maximum diameter the basket 5 and passes through the overflow port I from where it drains into the tub 3. When the switch II shunts the circuit through. the electrcmagnet 24 the float I3 is no longer held in its upper position and is again responsive only to the accumulation of water in the tub 3. Since the motor and consequently the drain pump is operating continuously during the entire spin cycle, any water accumulated in the tub 3 will be promptly exhausted, the float It will fall. and in response to its fall the switch arm 26 of the switch 23 will return to its normal position in engagement with the upper contact 2?. This will complete. a circuit through the solenoid 52 to open the hot water valve 9 and supply hot water to the basket 5. Shortly after the beginning of the spin cycle, as shown in Fig. 6, the switch IV is opened by the program controller and the circuit to thesolenoid I2 is interrupted, shutting off the hot water. Then the switch III is permitted by the program controller to close so that the solenoid I lior the cold water valve 8 is placed in parallelrelation with the solenoid ii for the hot water valve 5. Consequently, upon the next closing of the switch IV, a circuit will be made through both solenoids to open the hot and the cold water valves to supply a warm water mixture to the machine. Since the switch III remains closed for the duration of the operation of the machine, warm water only will be supplied in all subsequent operations.

At the close of the-spin period the switch II is opened by the program controller cam, breaking the circuit to the main motor winding, whereupon the motor will coast to'a stop. In this particular arrangement the program controlling cams are driven by the main drive motor through suitable gear reductions so that certain switching operations necessary at the end of the spin cycle are accomplished during the coast period. By a suitable conventional circuit arrangement (not shown) a separate timer motor to drive the program control may be employed. During this coast period switch IV is permitted to close completing a circuit through the solenoids II and 12 for the hot and cold water valves 8 and 9. Warm water is then supplied through the spout it to the basket 5. The switch I is opened simultaneously with switch IV breaking the circuit to the spin solenoid 38 so that upon reenergization of the motor winding, the agitator and not the spin basket will be driven. When the basket 5 has filled with rinse water to the overflow ports I and sufficient water has accumulated in the tub 3 the float I3 is again raised depressing the plunger 25 and completing a circuit through the holding coil 24, the motor start relay SI and the motor winding 32. Then, as previously described, the starting capacitor 36 and the start winding 31 are temporarily placed in the circuit while the motor is coming up to speed. Depression of the plunger 25 has interrupted the circuit to the solenoids H and I2 so that no more rinse water is admitted. As before the electromagnet Z i prevents the float IS from falling when the water is exhausted from the tub 3, so the agitator 6 continues to flex the clothes for the duration of the rinse cycle. At the end of the rinse period switches I and II are closed and the spin opera tion previously described is repeated. Following the second spin operation the program controller opens all of the switches and the full series operations have been completed.

It is now apparent that the electromagnet 2d must be energized to provide means of maintain.- ing the switch arm 26 in engagement with contact 28 to complete the circuit through the motor winding 32, except when both switches I and II are closed. When switches I and II are closed the electromagnet Ell is shunted out and the hold in circuit becomes ineffective, but, of course, it is now unneeded because the motor winding is separately energized. Consequently, my hold-in circuit is effective only during the cycles in which the further operation of the machine would ordinarily depend upon water accumulation within the tub and consequently make it necessary for the float to be kept in a raised position to simu late this condition of accumulated water.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made; and I therefore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a washing machine having a basket including a washing means, an overflow tub, a main drive motor for the clothes casket washing means, a drain pump for overflow tub driven by said motor, the combination of an electrically operated valve for supplying water to said basket, a water level switch responsive to the depth of the water accumulated in said overflow tub, and series connected electromagnetic means energized'by the operation of said water level switch for thereafter holding said water level switch closed and said motor energized regardless of the depth of water in said tub.

2. In a a clothes washing machine having a clothes basket, an overflow tub below said basket, a motor operated program control switch, a main drive motor, a drain pump for said overflow tub driven by said main drive motor, an electrically operated valve for supplying water to said basket, and a switch responsive to the water accumulation in said tub; a control comprising first and second parallel circuits for said main drive motor, said program control switch completing said first circuit, said second named switch completing said second circuit, and electromagnetic means energized by said second circuit holding said second named switch closed regardless of the accumulation of water in said tub but rendered inoperative by the completion of said first circuit.

3. In a clothes washing machine having a clothes basket, an overflow tub below said basket, a motor operated program control switch, a main drive motor, a drain pump for said overflow tub driven by said main drive motor, an electrically operated valve for supplying water to said basket and a switch having a first normal position and a second position to which it is moved in response to water accumulation in said overflow tub; a control comprising a first and second parallel circuit for said main drive motor and a third circuit for said electrically operated valve, said program control switch completing said first circuit, said second named switch in its second position completing said second circuit and in its first position completing said third circuit, and electromagnetic means energized by said second circuit for holding said second named switch in its second position regardless of the water accumulaticn in said tub.

i. In a clothes washing machine having a clothes basket, an overflow tub below said basket, a motor operated program control switch, a main drive motor, a drain pump for said overflow tub driven by said main drive motor, an electrically operated valve for supplying water to said basket and a switch having a first normal position and a second position to which it is moved in response to water accumulation in said overflow tub; a control comprising a first and second parallel circuit for said main drive motor and a third circuit for said electrically operated valve, said program control switch completing said first circuit, said second named switch in its second position completing said second circuit and in its first position completing said third circuit, and electromagnetic means energized by said second circuit for holding said second named switch in its second position regardless of the water accumulation in said tub but rendered inefiective by the completion or said first circuit.

5. In a clothes washing machine, a spin basket for receiving liquid and clothes to be washed and centrifugally dried, washing means in said basket, a tub for receiving overflow liquid from the spin basket, said basket having an overflow opening to the tub defining the basket water level for washing, a mechanism including a main drive motor for actuating the washing means, electroresponsive means for supplying liquid to said basket for washing, means operated by said main drive motor for exhausting continuously the overflow liquid from said tub, a, switch responsive to a predetermined accumulation of water in said tub for interrupting a circuit to said liquid supply means and simultaneously completing a circuit to said main drive motor for washing, and means energized by said motor circuit for holding said second named switch in its motor circuit completing position during the washing action.

6. In a clothes washing machine, a spin basket for receiving wash water and clothes, a clothes agitator in said basket, a tub for receiving overflow water from said basket, said basket having a plurality of overflow openings defining the water level for washing, an electric motor, a mechanism driven by said motor for oscillating said agitator and spinning said basket, electroresponsive means for shifting said mechanism between wash and spin including a normally open time switch effective upon closing to shift said mechanism to spin, means biasing said mechanism shifting means to wash position, water supply means for said basket, a pump operated continuously by said motor for draining said overflow tub, a switch responsive to a predetermined depth of water in said tub simultaneously to complete a circuit to said motor for washing and to interrupt said water supply, and electromagnetic means energized by said motor circuit for holding said second named switch in its motor circuit completing position, said electromagnetic means being rendered ineffective by the closing of said time switch.

7. In a combined clothes washing and extracting machine, a clothes receptacle with a substan tially imperforate lower portion and a plurality of overflow openings in its upper portion, a clothes agitator within said receptacle, a water overflow tub below and partially enclosing said receptacle, a float within said tub responsive to an accumulation or water therein, switch means actuated by said float, a liquid supply system for said receptacle rendered inoperative through said switch means by a predetermined elevation of said float, a drive motor, electroresponsive means operative in one position for connecting said motor f or oscillating said agitator for washing and operative in a second position for connecting said motor for spinning said receptacle for extraction, an electric circuit for said motor, means for energizing said motor circuit for washing including a normally open switch closed in response to the rise of said float, a pump operated continuously by said motor for said overflow tub, electromagnetic means for holding said float in its raised position for a predetermined time after said tub is emptied, and independent switch means for energizing said motor circuit for extraction and de-energizing said electromagnetic means.

8. In a washing machine having a clothes basket, an overflow tub, a main drive motor, a drain pump for said overflow tub driven continuously by said motor, the combination or an electrically operated Valve for supplying water to said basket, a switch responsive to the depth of the water accumulated in said overflow tub, and electromagnetic means energized in series with said main drive motor by the operation of said switch for thereafter holding said switch closed regardless of the depth of water in said tub.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,305,15 Gilbert Dec. 15, 1942 2,425,378 Lindemann Aug. 12, 194? 2,430,668 Chamberlain Nov. 11, 19 i? 2,561,257 Woodson July 17, 195i 

